Zirconium hydroxide supported metal and heteropolyacid catalysts

Abstract

The present invention is directed to novel catalyst compositions, their preparation, and their use in a selective paraffin isomerization process. The solid acid catalyst compositions comprise a zirconium hydroxide support, a Group VIII metal, and a heteropolyacid selected from the group consisting of the exchanged aluminum salt of 12-tungstophosphoric acid, the exchanged salt of 12-tungstosilicic acid, and mixtures thereof. The use of said catalysts in an isomerization process comprises contacting said catalysts with a feed comprising Cn or Cn+ paraffins, wherein n=4.

What is claimed is: 
     
       1. A solid acid catalyst composition comprising a zirconium hydroxide support about 0.01 to about 10 wt. % of a Group VIII metal and about 0.01 to about 60 wt. % of an exchanged heteropolyacid salt selected from the group consisting of the exchanged aluminum acid salt of 12-tungsto- phosphoric acid, the exchanged aluminum acid salt of 12-tungstosilicic acid, and mixtures thereof. 
     
     
       2. A catalyst composition according to claim 1 wherein said Group VIII metal is selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, and mixtures thereof. 
     
     
       3. A catalyst composition according to claim 2 wherein said Group VIII metal is a Group VIII noble metal. 
     
     
       4. A catalyst composition according to claim 3 wherein said Group VIII noble metal is platinum. 
     
     
       5. A solid acid catalyst composition according to claim 1, said heteropoly acid is the exchanged aluminum salt of 12-tungstophosphoric acid and said Group VIII metal is platinum. 
     
     
       6. A process of preparing a solid acid catalyst comprising a support, about 0.01 wt. % to about 10 wt. % of a Group VIII metal, and about 0.01 to about 60 wt. % of an exchanged heteropolyacid salt comprising the steps of (a) impregnating a heteropolyacid selected from the group consisting of the exchanged aluminum acid salt of 12-tungstophosphoric acid, the exchanged aluminum acid salt of 12-tungstosilicic acid, and mixtures thereof onto a zirconium hydroxide support;   (b) impregnating Group VIII metal onto said support before, during, or subsequent to step (a);   (c) activating said impregnated zirconium hydroxide support prior to and following said impregnation step (b) if said Group VIII metal is impregnated subsequent to step (a) or activating said impregnated support after said impregnation of a heteropolyacid salt if said Group VIII metal is impregnated before or during step (a) to form a catalyst.   
     
     
       7. A process of preparing a solid acid catalyst according to claim 6 wherein said Group VIII metal is impregnated via a solution selected from the group consisting of chloroplatinic acid, ammonium tetrachloroplatinate (II), ammonium hexachloroplatinate (IV), chloroiridic acid, tetrammine platinum hydroxide, tetrammine platinum chloride, and dinitrodiammineplatinum (II).